I have cloned my TEST instance from PROD and my database is running but when I try to bring up the Application and access the front end my APPS user account gets locked on database and I am not getting redirected to LOGIN PAGE of EBS.

Just a guess, but are there any scripts which are trying to do connect with the APPS password of production, but fail because the APPS password change is done later, but the APPS account gets locked partly because of aggressive locking settings ?

I have cloned my TEST instance from PROD and my database is running but when I try to bring up the Application and access the front end my APPS user account gets locked on database and I am not getting redirected to LOGIN PAGE of EBS.

I solved the issue yesterday, sorry that I am updating late here. What had happened is that I usually restore the COLD Backup for clone that I take on Sundays. So I restored last Sunday's backup. And I had not run adpreclone this Sunday before taking backup. On top of that I changed PASSWORDS of APPS,SYSADMIN and another frontend USER ERPADMIN.

And I ran adpreclone yesterday and copied the clone directories on both Tiers. So the new password that I was using while running adcfgclone conflicted with the old password that was stored in the FND_USER and FND_ORACLE_USERID tables.

is exactly for that case of messing up the APPS password by having run ALTER USER at some point. But you didn't, you changed the password in the correct way (I assume), but by means of different backups, the pass just wasn't what you thought it was (passwords have that effect), potentially causing locks, etc.